Wireless backhaul service typically refers to wire-line communication links between a central office network and its wireless cell sites that communicate with external cell (i.e., cellular or mobile) phones wirelessly within their transmission ranges. In other words, a wireless backhaul system transfers or hauls communication information between its central office network and cell sites. The cell sites then communicate wirelessly with external cell phones. The cell sites, the wireless backhaul system, and the central office network constitute the basic structure of a wireless service network.
A typical wireless backhaul system includes T1 links that are connected to cell sites for transferring communication (e.g., voice, data, or video) traffic from the cell sites to a local exchange network. T1 means any digitally multiplexed telecommunication carrier system that runs at the 1.544 Megabit per second line rate. The communication traffic is then routed via the local exchange network to a central office network via another T1 communication link.
One drawback associated with this prior art approach is the bandwidth constraint on the T1 links as the transfer rate offered by a T1 line is only approximately 1.544 MB (Mega Bits) per second. This is certainly not sufficient to support voice, high-speed data (e.g., emails, Internet), and video transfer services, thus making the wireless backhaul system the bottleneck in providing high speed wireless communication services. Another drawback is the cost constraint as the T1 lines typically use copper wires, which are relatively expensive.
One prior solution to the above drawback is to migrate to Ethernet-based wireless backhaul system which provides significantly higher bandwidth (e.g., approximately 100 MB per second transfer rate) to transport wireless backhaul traffic between the cell sites and the central office network, as is shown in FIG. 1. As can be seen from FIG. 1, the prior art Ethernet-based wireless backhaul system 50 includes a number of Ethernet switches 31 through 31n, each connected to one of the cell sites 11-11n via one of the T1 links 20. The Ethernet switches 31-31n are connected to an Ethernet network 41 via Ethernet links 40. The Ethernet network 41 is then connected to routers (not shown in FIG. 1) within the central office network 45 via a high speed Ethernet link 42.
However, disadvantages are associated with this prior art approach. One disadvantage is that the Ethernet links 40 and 42 need to be repeated approximately every one hundred meters (e.g., approximately three hundred thirty feet). This will significantly increase the cost of the backhaul system if the distances from the cell sites to the central office network are significantly longer than 100 meters. Another disadvantage is that the prior art Ethernet-based wireless backhaul system also requires active devices or equipment within the system, thus increasing the cost of deploying and maintaining the system.
Thus, what is needed is a wireless backhaul system that transports long distance communication traffic between the cell sites and the central office network at a high transfer rate cost effectively.